Couplings used to interconnect fluid conveying tubes or conduits are found across many different industries, and special requirements may exist in each industry to address a number of standards. Many of the standards involve safety requirements to ensure the coupling creates a fluid tight seal across the facing ends of the tubes or conduits. For fluid conveying tubes that convey fuel, there is always a concern in the design of couplings to ensure that the design can provide means to dissipate electrostatic charges that will build up between insulated sections of the coupled tubes/conduits. A stored electrostatic charge may give rise to an electrical spark hazard in the presence of vaporized fuel. Discharge of the spark by grounding or by flexing of the coupling in such a manner to bring metallic parts of the coupling into contact with another may cause an instantaneous combustion of any vaporized fuel present at the time, which in turn can cause ignition of the fuel conveyed in the tubes. Other causes of potential ignition include lightning strikes. Therefore, one requirement for a coupling may be to provide the capability to dissipate both dynamic and static electrical charges.
One solution incorporated in couplings is to provide an electrical jumper, also referred to as a bonding jumper, to eliminate the hazard of differential electrostatic charges. In short, a bonding jumper provides an electrically conductive connection between coupled sections of a tube or conduit to prevent build up of electrostatic charges. Electrical jumpers may be exteriorly or interiorly mounted. Exteriorly mounted jumpers may include a piece of flexible conductive metal or cable that is detachably secured to the metallic flanges or ferrules of the facing ends of the tubes. Interiorly mounted jumpers may include leaf-spring type constructions mounted within the coupling and placed in contact with the flanges or ferrules forming the ends of the fluid conveying members to be connected.
As designs of couplings have progressed, other improvements have been incorporated within these designs to address various performance standards. Particularly for fluid conveying conduits that convey flammable liquids and installed within constrained spaces, some coupling designs have been developed to ease a user's manipulation of the coupling for connecting and disconnecting the adjacent tubes/conduits. However, despite certain improvements, there is still a need to provide a coupling design that maximizes not only the certainty that the coupling can be easily and consistently latched or locked, but also that the coupling design is of a lightweight yet robust construction capable of withstanding loading conditions where the coupling is installed.
One type of construction for a coupling includes a two-piece “clamshell” coupling in which two coupling members or halves are connected to one another about a hinge, and a latching mechanism is used to lock the coupling over connected fluid conveying members. One example of such a clamshell type coupler includes the U.S. Pat. No. 8,075,024. This reference more specifically discloses a coupling assembly for interconnecting fluid conveying members each having a ferrule captured within the coupler, along with a sleeve that circumferentially surrounds the ferrules. A bonding wire construction is provided to electrically bond the respective coupling members to the ferrules of the fluid conveying members. A releasable latching mechanism is configured to releasably secure the ends of the coupling members in a closed or locked position.
Another example of a clamshell type coupler includes the U.S. Pat. No. 6,880,859. This particular reference also discloses a coupler especially adapted for connecting confronting ends of fluid conveying members each having ferrules with annular sealing O-rings, and a sleeve that circumferentially surrounds the ferrules. This reference more specifically discloses a particular construction for an externally mounted bonding wire and a redundant latching mechanism.
Despite the numerous designs known for coupling devices, there is still a need to provide a coupling device that adopts important safety features, yet is easily and reliably manipulated by a user.